Counter track joints are basically known from DE 102 20 711 A1 in which joints with 6 balls or 8 balls are presented. Here, the type of ball tracks corresponds to the type known per se from Rzeppa Joints (RF joints) and from the undercut free joints (UF joints). This means that the center lines of the ball tracks are composed of uniform radii (RF joint) and that the latter are made up of radii and straight elements which are parallel to the axis (UF joint).
In the counter track joints described, the axial opening directions of the track pairs alternate over the circumference, which gives rise to the counter track joint type. These known counter track joints are, however, limited to approximately 45° with respect to their articulation angle, because if this articulation angle is exceeded, a first ball in the joint articulation plane leaves the first track pairs.
DE 103 37 612 A1 also discloses ball track joints in which the track center lines of the first track pairs (which have an angle of aperture whose opening direction points towards the base of the joint when the joint is extended) are configured in such a way that the angle of aperture experiences a reversal of its opening direction when the joint is articulated starting from a certain articulation angle. This is implemented in particular by virtue of the fact that the track center lines of the ball tracks of the first track pairs are S-shaped and thus each have a turning point.
DE 100 60 220 A1 discloses, inter alia, counter track joints in which the center lines of the first outer ball tracks have a turning point near to the joint opening so that the center lines of the first outer ball tracks are S-shaped. The same applies to the center lines of the first inner ball tracks of the joint inner part owing to the consideration of symmetry. The maximum articulation angle of these counter track joints could thus be increased further.
Finally, reference is made to a counter track joint with a track turning point such as is described in WO 2006/048032. The counter track joint described therein is intended to be used in particular to reduce the friction between the ball cage and joint outer part or joint inner part. For this purpose, it is proposed that the track center lines of the first track pairs each have a turning point and that the center point angle in the turning points in relation to the joint center plane is greater than 4 degrees in each case. This ensures that the joint operates as a counter track joint in service life operation. Service life operation is considered to be operation within the service life angle at which the service life of the joint is reached with-out damage under alternating load.
With respect to the known joint arrangements there is also the need for a higher loadability, in particular in the case of simultaneously high articulation angles. At the maximum articulation angle, the balls move to a front edge of the surrounding outer part and there they can leave the cage which is guiding them. Furthermore, there are joint arrangements in which the front cross section of the ball cage is weakened by a particularly large mounting bore which is required to mount the inner race. Finally, the ball track depth which can be achieved with such joints and which also influences the service life of the joint does not always meet the requirements which are set. This is the case in particular with ball tracks which open towards the shaft when the joint arrangement is extended. With this type of ball track the depth of the ball track is greatly reduced in the internal region of the joint outer part.